There are 2 projects currently being pursued in my laboratory; both dealing with regulation of immune responses to chronic antigen exposures; one project is focused on self-erythrocytes and the other on Hepatitis B Virus antigens.  In the first project, we are studying the response to self erythrocytes (MRBC) in normal BALB/c mice and in NZB mice that spontaneously develop anti-MRBC responses.  We have demonstrated that both T and B cells reactive to self erythrocytes are present in normal as well as the autoimmune mice.  In culture, development of anti-erythrocyte autoantibody responses depends upon CD4 positive helper T cells and can be suppressed by CD8 positive T cells.  We are currently defining the epitopes on the MRBC antigen that are targets of the autoantibodies made by NZB mice in order to determine which are the initiating epitopes, to determine whether these are the same in all mice that develop anti-MRBC responses, and to focus our regulation studies on those targets that occur early in the autoimmune response.